A questionnaire for a conceptual framework and interdisciplinary public health research using the Delphi technique – development and validation

Background The Delphi technique has become established in public health research, yet there is a lack of methodological standards in questionnaire development. We here demonstrate how the Delphi technique can be used in an interdisciplinary public health topic for framework development, and we highlight methodological challenges and possible solutions. Methods We developed the questionnaire through a comprehensive literature review and the generation of an item pool based on the rules of item construction. We used cognitive interviews, Delphi experts’ assessment and group discussions to refine the questionnaire and to ensure content validity. Finally, we pre-tested the online questionnaire on LimeSurvey. Results The questionnaire consists of three main sections, namely gender (norms), the social environment and the mental health of adolescents, and another section on the expert’s characteristics. The questionnaire comprises a total of 32 questions and includes rating and ranking questions, contentrelated and comment questions, open and closed questions as well as questions on personal characteristics and evaluation questions. Conclusion Interdisciplinary researchers need to be involved in the development process of the questionnaire to address challenges related to interdisciplinarity. Researchers using the Delphi technique should consider certain aspects of the development process, such as comprehensively preprocessing the content, disentangling the theoretical concepts, reducing the complexity, providing more structure and clarity, and ensuring that the length of the questionnaire is manageable. Future research should focus on developing methodological guidelines and testing their applicability for different objectives of the Delphi technique (e.g. framework development).